Periodontal disease is the principle oral complication associated with diabetes mellitus. Chlorhexidine gluconate (Peridex, Proctor & Gamble Co.) is an oral antimicrobial mouthrinse that has been used as a safe and effective agent in preventing and controlling plaque formation in selected population. Since periodontal diseases are plaque-induced infections, the purpose of this study is to evaluate the effect of chlorhexidine gluconate mouthrinse on periodontal diseases in patients with Type II diabetes mellitus. This study will also examine the relationships between diabetes control, medication compliance and the efficacy of chlorhexidine mouthrinse on periodontal disease in this patient population. This study method is a randomized double-blind, placebo-controlled design. A sample of 50 patients with Type II diabetes mellitus and early to moderate periodontal disease will be recruited and randomly assigned to a treat (chlorhexidine gluconate 0.12% mouthrinse) or control (placebo mouthrinse) group, and stratified by diabetes control and periodontal disease status. Following dental cleaning and examination, subjects will be asked to use study mouthrinse twice a day for six months. During the six month duration of the study, subjects will be asked to return monthly to the clinic for a nurse interview and compliance assessment, as well as at three month interval for oral measurements, laboratory assessment (glycosylated hemoglobin) and dental prophylaxis. To date, 19 patients have been eligible, participated in, and completed the study. Due to difficulty recruiting subjects who meet eligibility criteria, it was decided that data would be analyzed to determine whether or not to continue the study. Data entry and analysis are in progress.